<FlowDocumentScrollViewerSelectionBrush="Pink"SelectionOpacity="0.7"><FlowDocument><Paragraph><Bold>Neptune</Bold> (planet), major planet in the solar system, eighth planet
from the Sun and fourth largest in diameter. Neptune maintains an almost constant
distance, about 4,490 million km (about 2,790 million mi), from the Sun. Neptune
revolves outside the orbit of Uranus and for most of its orbit moves inside the
elliptical path of the outermost planet Pluto (see Solar System). Every 248 years,
Pluto’s elliptical orbit brings the planet inside Neptune’s nearly circular orbit
for about 20 years, temporarily making Neptune the farthest planet from the Sun.
The last time Pluto’s orbit brought it inside Neptune’s orbit was in 1979. In
1999 Pluto’s orbit carried it back outside Neptune’s orbit.
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